Aaron Ramsey limped off before the hour mark of Arsenal's win over BayernGetty Images

Arsenal duo Aaron Ramsey and David Ospina have been ruled out of action for at least a month, after suffering a hamstring and shoulder injury respectively. Ramsey limped out of the Champions League win over Bayern Munich while Ospina returned from international duty with Colombia with the problem. This puts the pair out of the club's next five games, which the Champions League return trip to Bayern Munich and the North London derby against Tottenham Hotspur.

Manager Arsene Wenger has attributed Ramsey injury, which saw him replaced by Alex Oxlade-Chamberlain after 57 minutes of the 2-0 win over Bayern, to him playing twice for Wales during the recent international break. The 24-year-old played the full 90 minutes in the European Championship qualifiers against both Bosnia and Herzegovina and Andorra – his second appearance coming after Chris Coleman's side had already qualified for the finals in France next summer.

A similar fate befell Gareth Bale after he too played a full part in Wales' two matches, with the Real Madrid winger having not played for a month due to a thigh problem before the international double-header. The 26-year-old started for Real against Levante on 17 October but was substituted with another injury; leaving manager Rafael Benitez to label Bale's commitments for club and country "difficult to manage".

Wenger has also taken aim at the Football Association of Wales and says they are to blame for Ramsey's current plight, which is expected to see him sidelined for the next four weeks. The 24-year-old is expected to miss the games against Everton, Sheffield Wednesday, Swansea City, Bayern and Tottenham.

"He had a scan today but he's out," Wenger told the official Arsenal website. "I believe he will be out until after the next international break. With the [last] international break, the fact that he played against Andorra certainly cost Bale and him as well."

The injury to Ospina saw Petr Cech return in goal for Arsenal in the Champions League, after the summer signing from Chelsea initially missed their first two group matches. The Czech Republic stopper looks set for an extended run in the team as the Gunners play in three different competitions over the next 17 days.

"David Ospina is out for our next game and certainly until the next international break. For [Danny Welbeck, Jack Wilshere and Tomas Rosicky], you can say around the New Year."

Victories in their first meetings with both Bayern and Tottenham this season have given Wenger confidence his side can cope without the influential quintet. Goals from Olivier Giroud and Mesut Ozil helped them overcome the German champions on Tuesday 20 October, while Mathieu Flamini netted twice to beat Spurs in the Capital One Cup tie at White Hart Lane.